High-speed urbanization causes that indoor and outdoor air is all to a certain extent polluted by dusts and toxic gas, combined with building materials, furniture and electrical equipments, etc. continue to release large amounts of VOCs (toxic and harmful volatile organic compounds) indoors, making the indoor air quality becomes worrying, and affects people's healthy and comfortable lives directly.
At present, the purification methods of air purifiers on the market mainly include chemical reaction methods, physical adsorption technology, ozone anion technology, nano-photocatalys is technology, low temperature plasma technology, plant purification and biodegradation, etc. Most air purifiers are all required to replace internal arrangements regularly, which results in expensive maintenances thereof. Most mechanical purifiers can only filter out dusts in air, but can not remove VOCs effectively. In general, plant air purifiers use the roots, stems and leaves of the plant to absorb the VOCs in the air to purify the air, such as the plant air purifier and the system thereof disclosed in Chinese Patent No. ZL201310214831.4. In such kind of plant air purifiers, plant body is the core system of air purification, and the plant's own air purification effect is limited and not targeted, if there are not any other means of auxiliary air purification to employ, the purification effect of plant air purifiers will difficult to achieve the desired level. Microbiological purification of air is mainly use the assimilation of microbial populations, which are of wide distribution, vigorous metabolism and rapid propagation, to degrade the VOCs in air, so as to achieve the purpose of purifying air, such as the air purifier for removing formaldehyde as disclosed in the Chinese Patent Application No. 201410607342.X. However, it is required to replenish with microorganisms often because they are dead-prone, and the usage is cumbersome and costly expensive.
Chinese Patent No. ZL201420592198.2 discloses an indoor air purifier which is provided with a biological purification layer and a plant planting position. The air purifier enables a symbiosis of plant roots and microorganisms in water by means of extending the plant roots under water, and meantime takes advantage of the purification effect of plants and microorganisms to build a complete ecosystem so as to secure the growth of plants, the long-term survival of microorganisms and to remove dusts and VOCs effectively. Nevertheless in this technology only when the plant roots extend under the water surface in the water tank, then the symbiosis of the plants and the microorganisms can be secured. This configuration has a certain limitation to the water level where the water level should not be too much low. Because the plant roots are positioned in the water tank, mud adsorbed on the roots, broken or falling roots may also be in the water tank, which may affect the water circulation and the purification effect.